Solar Panel Warranties Explained: What NI Homeowners Need to Know

Why Solar Panel Warranties Matter

A solar panel system is a long-term investment. You are spending thousands of pounds on equipment that is expected to generate electricity for 25 years or more, so the warranties backing that equipment are a critical part of the purchase decision.

Unfortunately, warranties are often glossed over during the sales process. Homeowners in Northern Ireland regularly tell us they were not given clear information about what their warranty actually covers, how long it lasts, or what would happen if something goes wrong.

This guide breaks down the different types of solar panel warranty, what to look for, and how to protect yourself before you sign on the dotted line.

The Three Types of Solar Panel Warranty

There is no single “solar panel warranty.” In practice, your system is covered by three separate warranties, each from a different party and covering different things.

1. Product Warranty (Manufacturer)

The product warranty covers manufacturing defects in the panels themselves. If a panel fails due to faulty materials, poor workmanship during manufacturing, or a design flaw, the manufacturer will replace it.

Typical product warranty lengths vary by brand tier:

• Premium brands (SunPower, REC, LG): 25 years
• Mid-range brands (JA Solar, Trina, Canadian Solar): 12 to 15 years
• Budget brands: 10 years or less

A longer product warranty generally reflects the manufacturer’s confidence in their panels. It is worth noting that some brands have recently extended their product warranties to match their performance warranties, offering a full 25-year product guarantee.

2. Performance Warranty (Manufacturer)

The performance warranty guarantees that your panels will still produce a minimum percentage of their rated output after a set number of years. Almost all reputable manufacturers offer a 25-year performance warranty, but the guaranteed output level varies.

A typical performance warranty might guarantee:

• At least 97% of rated output in year one
• A maximum degradation of 0.4% to 0.6% per year
• At least 80% to 85% of rated output at year 25

Premium panels tend to offer tighter degradation guarantees, sometimes promising 92% output at year 25. Over 25 years, the difference between an 80% and a 92% guarantee adds up to a meaningful amount of electricity.

If your panels degrade faster than the warranty states, the manufacturer is obliged to repair, replace, or compensate you. However, proving underperformance requires proper monitoring data, which is another reason to keep a close eye on your system’s output.

3. Workmanship Warranty (Installer)

The workmanship warranty comes from your installer, not the panel manufacturer. It covers the quality of the installation itself: the roof fixings, wiring, sealing of any roof penetrations, and the overall setup of the system.

Workmanship warranties in Northern Ireland typically range from 2 to 10 years, depending on the installer. Some of the better NI installers offer workmanship warranties of 5 to 10 years. Be cautious of any installer offering less than 2 years.

This warranty matters because many common post-installation problems (roof leaks, loose connections, incorrectly configured inverters) are installation issues rather than product defects. If your panels are fine but the wiring fails because it was poorly routed, that is a workmanship problem.

Inverter Warranties

Your inverter is the component most likely to need replacement during the lifetime of your solar system. It works harder than any other part, converting DC electricity to AC every day, and it has electronic components that wear out.

Standard inverter warranties are:

• String inverters (SolarEdge, GoodWe, Solis): 5 to 12 years, with some offering paid extensions to 20 or 25 years
• Microinverters (Enphase): 25 years as standard

Since your panels will last 25 years or more, a 5-year inverter warranty means you will almost certainly need to pay for a replacement at some point. If your inverter comes with a shorter warranty, ask your installer about extended warranty options at the point of purchase. It is nearly always cheaper to buy an extension upfront than to pay for a replacement later.

What Can Void Your Warranty

Understanding what voids a warranty is just as important as understanding what it covers. Common pitfalls include:

• Non-MCS installation. Most manufacturers require installation by an MCS-certified installer. If your system was installed by someone without MCS accreditation, the manufacturer can refuse a warranty claim.
• Unauthorised modifications. Adding panels, changing the inverter, or altering the wiring without using a qualified installer can void both manufacturer and installer warranties.
• Improper cleaning. Using a pressure washer, abrasive chemicals, or walking on panels can cause damage that is not covered.
• Failure to maintain. Some warranties require evidence of reasonable maintenance. While solar panels need very little upkeep, complete neglect (allowing heavy debris buildup, ignoring obvious damage) can be grounds for a declined claim.
• Extreme events. Most product warranties exclude damage from extraordinary events such as lightning strikes or severe storms. Your home insurance should cover these situations instead.

Making a Warranty Claim

If you believe your panels or inverter are underperforming or faulty, the process typically works as follows:

1. Document the issue. Gather monitoring data, photographs, and any records of when the problem started.
2. Contact your installer first. For workmanship issues, your installer is the first port of call. For product issues, many installers will handle the manufacturer claim on your behalf.
3. Contact the manufacturer directly if your installer is unresponsive or has ceased trading.
4. Expect an inspection. The manufacturer or installer may send an engineer to inspect the system before approving a claim.
5. Resolution. Depending on the issue, you may receive a replacement panel, a replacement inverter, a repair, or financial compensation.

Keep all your paperwork. Your MCS certificate, installation contract, warranty documents, and monitoring data are all valuable if you ever need to make a claim.

Insurance-Backed Guarantees

An insurance-backed guarantee (IBG) is an additional layer of protection that covers your workmanship warranty if your installer goes out of business. Given that the solar industry in Northern Ireland has seen installers come and go, an IBG is well worth having.

With an IBG, if your installer ceases trading during the workmanship warranty period, the insurance company steps in to honour the warranty. This typically costs £50 to £150 as a one-off payment at the time of installation.

Ask your installer whether they offer an IBG and through which provider. If they do not offer one, that is not necessarily a red flag, but it is something to weigh up alongside other factors.

What to Check Before You Buy

Before committing to a solar panel installation in Northern Ireland, make sure you have clear answers to the following:

• What is the product warranty length for the specific panels being quoted? Do not accept vague answers. Get the exact model number and check the manufacturer’s warranty terms online.
• What is the performance warranty guarantee at year 25? Look for at least 80%, ideally higher.
• What inverter is being used, and what is its warranty? If it is less than 10 years, ask about extension options.
• What is the installer’s workmanship warranty? Get the length in writing and ask what it covers specifically.
• Is an insurance-backed guarantee available? If so, how much does it cost?
• Is the installer MCS-certified? This is non-negotiable for both warranty validity and eligibility for the Smart Export Guarantee.

The Bottom Line

A solar panel warranty is only as good as the company standing behind it. Choosing established panel brands with a track record in the market, pairing them with a reputable MCS-certified NI installer, and securing an insurance-backed guarantee gives you the strongest possible protection.

Do not let price alone drive your decision. A slightly cheaper quote with weaker warranties could cost you far more in the long run if something goes wrong and you have no recourse. Take the time to read the warranty documents, ask the right questions, and make sure you are covered for the full lifetime of your system.